The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Tone on 20.07. 2009 19:46

Title: Oil Pump
Post by: Tone on 20.07. 2009 19:46
Hi, I have taken off the timing cover to send the inner cover to Sean Hawker to have the oil seal done prior to fitting a belt drive.1st, the oil pump compartment was full of oil I don't think thats right? 2nd, there are 3 nuts to take off, also the worm drive gear (I think) is this part of the pump? what I mean is do you remove the left hand tread nuts and take off what looks like a spring,or does it all come off together with the pump?
Title: Re: Oil Pump
Post by: trevinoz on 20.07. 2009 23:24
Tone, you remove the oil pump 3 nuts, remove the left hand locknut and tab washer and wind off the worm gear. The oil pump will come with it. Note the correct size spanner or socket for the locknut and worm is 25/32".
The compartment will be full of oil.
Don't lose the flat washer under the worm gear.
Title: Re: Oil Pump
Post by: Tone on 21.07. 2009 08:01
Thanks Trev, Odd size of spanner, thats why its mullered!!
Title: Re: Oil Pump
Post by: trevinoz on 21.07. 2009 23:02
Funny about that size. I think, if my memory is not failing, that the swinging arm gearbox bolts and nuts are the same.
Title: Re: Oil Pump
Post by: Tone on 22.07. 2009 23:24
Trev, would that spanner size be Whitworth?
Title: Re: Oil Pump
Post by: trevinoz on 23.07. 2009 00:55
         no, it is an AF size. Or SAE if you like.
Title: Re: Oil Pump
Post by: Tone on 23.07. 2009 19:40
Sorry Trev, Where did you buy a 25/23" socket from? I,m having trouble getting one, Tone.
Title: Re: Oil Pump
Post by: beezalex on 23.07. 2009 19:55
20 mm socket works just fine.
Title: Re: Oil Pump
Post by: Lannis on 23.07. 2009 20:18
I've bought 19/32", 21/32", 23/32", and 25/32" wrenches for my three BSAs.  It's surprising how many nuts they fit perfectly, either by design or coincidence.  25/32" is 19.8 mm, so a 20 mm will be just a tad loose but likely will do fine.

I pick up odd wrenches at flea markets and swap meets.  It's surprising how many nice Craftsman or Klein or Snap-On tools are lurking in the bottom of odd boxes along with the Oriental junk ...

Title: Re: Oil Pump
Post by: LJ. on 23.07. 2009 21:59
25/32" is 19.8 mm

I could have done with borrowing your 25/32" wench/spanner this very evening Lannis. That bloomin nut holding the banjo on the back of the oil tank was awkward to get at. I was actually thinking that a 19.5mm spanner would have done it. My remedy? took the nut for a good filing down!  *whistle*
Title: Re: Oil Pump
Post by: chaterlea25 on 23.07. 2009 23:46
Hi Lannis and All,
Not wishing to upset you, I know the crank end nut is an oddball size,
but virtually all the nut sizes on BSA A7/10's are Whitworth sizes
with either whitworth or cycle thread forms
the only other odd thread besides BA on the electrics that I can think of at the moment
are the nuts on the back of the speedo, 0BA thread with a 3/16whit hex
here is a link to a comparison chart, there are loads on the net,
A good source of good quality Whit spanners are army surplus stores, I bought some really good quality ones at the store near here
John O R